Sapiens and Cognition : The Optimal Vertical Nervous System—The Last Threshold of Self-Organized and Self-Memorizing Increasing Complexity from Gametes to Embryo

Résumé En

From Antiquity to the nineteenth century, the human being was seen as an archetype from the metaphysical origin organized in the physical world around the verticality, monkeys belonged to another archetype able of quadrupedalism and bipedalism. In 1801 and 1802, Jean-Baptiste de Lamarck proceeded to a rupture by seeking a natural and functional explanation of human verticality since extinct monkeys in relation to climate changes. He opened the mind to self-organized processes between living systems and their environments. In 1868, Charles Darwin took up the Lamarckian theory with the gemmules hypothesis, looking for an explanation for the transmission of the macroscopic changes and their memorization at the microscopic scale of the sex cells. Memorization and self-organization were the implicit processes of transformism, the natural selection being a general concept waiting for better knowledge in bio-physicochemistry, i.e., in thermodynamics. This double evolutionary problematics, (1) the memorization of the transformation processes and (2) the neural straightening from quadrupedal primates to bipedal Homo sapiens, is confirmed but as a consequence of the macroevolution of the embryonic body plans and not as the result of postnatal biomechanical constraints. I have demonstrated for more than 30 years that the straightening was a progressive embryonic and phylogenetic process, saltationist and reiterated four times, starting systematically from the horizontal direction of the notochord. This process followed increasing complexity and duration of the neurulation with morphological reorganization along the cephalocaudal axis. The stability of the evolutionary trajectory over 40 million years up—despite successive emergent angular discontinuities separated by million years—allowed us to infer a new family of gametogenesis attractors which correspond to evolutionary properties transmitted since the emergence of unicellulars: the self-memorization of self-organized processes. In other words, self-organization which includes simultaneously its own memorization is the complex process that allowed the emergence of life whose principles are self-reproduction. Prokaryote diversification generated environmental increasing complexity. Then, eukaryotes and multicellulars became possible thanks to the increasing diversity and complexity of the environment but also thanks to self-memorization properties able to create and transmit the first ontogeny. Later, macroevolution could develop with a coherent reorganization of the body plan according to the rules of internal increasing complexity. The phylogenetic straightening of the central nervous system allows us to induce that gametes have inherited these macroevolutionary properties acting during embryogeny along the craniocaudal axis. This paradigmatic shift is coherent with the sciences of self-organization and opens debate on the future of our species because the verticality is reaching a physical limit for the vocal tract, the dental occlusion, and the cerebellum with psychomotor and cognitive consequences, whereas the relationships between the environmental complexity, the sex cells, the reproductive organs of the females, and the exponential complexification of the neurogenesis are still unknown.